I have a 12V battery and charger in my caravan. The charger operational at all times and connected to the battery terminals. I have been told that when the 12V lights are switched on that they draw current from the battery rather than the charger and that the charger merely replenishes the lost charge. This it was explained, was to facilitate battery cycling and promoted healthy batteries which I can understand.

Firstly, does the battery provide the current?
Secondly, if the battery is the source, how does the light discriminate between the battery and the charger as its source?

The question would require a schematic of the charger and lighting circuit to give an accurate answer. It may be just as simple as a diode isolating the charger when the battery is supplying current to a sensing circuit that opens a relay/turns off a transistor when there is current in the lighting wires.

the control box housing the charger is mounted in the most awkward place and is an absolute swine to remove so it will be difficult to have a look inside. Besides the manufacturers will not give me a diagram??

Could it be as simple as having a current limited charger say of 4A. Lets assume the load of the 12V lights is 12A. That would immediately have a drain on the battery of 8A which would be replenished while sleeping?

I have a 12V battery and charger in my caravan. The charger operational at all times and connected to the battery terminals. I have been told that when the 12V lights are switched on that they draw current from the battery rather than the charger and that the charger merely replenishes the lost charge. This it was explained, was to facilitate battery cycling and promoted healthy batteries which I can understand.

Firstly, does the battery provide the current?
Secondly, if the battery is the source, how does the light discriminate between the battery and the charger as its source?

Thanks
Andrew

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I think you were told wrong. If your lights are connected to the battery poles where the charger is connected to, then the electrons will flow more in the lower resistant path they will find usually from the charger clamps. Also for example if your charger supplies a steady 5A and your lights consume 5A you will be just trading charges and nothing to worry about. True that the solucion inside the battery loses its properties over time.

Thanks for that. I phoned the manufacturer and they still will not give me the circuit diagram but the technical guy did confirm that the lights will not work unless the battery is connected. From this I have to assume that the electrons come from the battery rather than the charger. The battery clamps have both the charger and light connections connected to them.

This would lead me to believe that there is some circuitry, as beenthere mentioned, that controls matters.

I was just curious as to how it worked that was all, my very finite understanding of electrons is not sufficient to arrive at an answer.